Masked-Speech Recognition for Linguistically Diverse Populations: A Focused Review and Suggestions for the Future

Purpose: Twenty years ago, von Hapsburg and Peña (2002) wrote a tutorial that reviewed the literature on speech audiometry and bilingualism and outlined valuable recommendations to increase the rigor of the evidence base. This review article returns to that seminal tutorial to reflect on how that advice was applied over the last 20 years and to provide updated recommendations for future inquiry.

Method: We conducted a focused review of the literature on masked-speech recognition for bilingual children and adults. First, we evaluated how studies published since 2002 described bilingual participants. Second, we reviewed the literature on native language masked-speech recognition. Third, we discussed theoretically motivated experimental work. Fourth, we outlined how recent research in bilingual speech recognition can be used to improve clinical practice.

Results: Research conducted since 2002 commonly describes bilingual samples in terms of their language status, competency, and history. Bilingualism was not consistently associated with poor masked-speech recognition. For example, bilinguals who were exposed to English prior to age 7 years and who were dominant in English performed comparably to monolinguals for masked-sentence recognition tasks. To the best of our knowledge, there are no data to document the masked-speech recognition ability of these bilinguals in their other language compared to a second monolingual group, which is an important next step. Nonetheless, individual factors that commonly vary within bilingual populations were associated with masked-speech recognition and included language dominance, competency, and age of acquisition. We identified methodological issues in sampling strategies that could, in part, be responsible for inconsistent findings between studies. For instance, disparities in socioeconomic status (SES) between recruited bilingual and monolingual groups could cause confounding bias within the research design.

Conclusions: Dimensions of the bilingual linguistic profile should be considered in clinical practice to inform counseling and (re)habilitation strategies since susceptibility to masking is elevated in at least one language for most bilinguals. Future research should continue to report language status, competency, and history but should also report language stability and demand for use data. In addition, potential confounds (e.g., SES, educational attainment) when making group comparisons between monolinguals and bilinguals must be considered.